/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4; fill-column: 100 -*- */
/*
 * Copyright the Collabora Online contributors.
 *
 * SPDX-License-Identifier: MPL-2.0
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 */

/*
 * Utilities for file server operations.
 * Functions: preprocessFile(), preprocessAdminFile()
 */

#include <config.h>

#include <common/JsonUtil.hpp>
#include <common/StringVector.hpp>
#include <common/base64.hpp>
#include <wsd/FileServer.hpp>

#include <cctype>

PreProcessedFile::PreProcessedFile(std::string filename, const std::string& data)
    : _filename(std::move(filename))
    , _size(data.length())
{
    std::size_t pos = 0; ///< The current position to search from.
    std::size_t lastpos = 0; ///< The last position in a literal string.

    do
    {
        std::size_t newpos = data.find_first_of("<%", pos);
        if (newpos == std::string::npos || newpos + 2 >= _size)
        {
            // Not enough data to parse a variable.
            break;
        }

        assert(newpos + 2 < _size && "Expected at least 3 characters for variable");

        if (data[newpos] == '<')
        {
            if (newpos + 5 < _size && data.compare(newpos + 1, 4, "!--%") != 0)
            {
                // Just a tag; continue searching.
                pos = newpos + 1;
                continue;
            }

            std::size_t nestedpos = data.find_first_of("<>", newpos + 1);
            if (nestedpos != std::string::npos && data[nestedpos] == '<')
            {
                // We expected to find the end of comment before a new tag.
                // Resume searching.
                pos = nestedpos;
                continue;
            }

            // Find the matching closing comment
            std::size_t endpos = data.find_first_of('>', newpos + 1);
            if (endpos == std::string::npos)
            {
                // Broken comment.
                break;
            }

            // Extract variable name.
            const std::size_t varstart = data.find_first_of('%', newpos);
            if (varstart == std::string::npos || varstart > endpos)
            {
                // Comment without a variable.
                pos = endpos + 1;
                continue;
            }

            std::size_t varend = varstart + 1;
            while (varend < endpos)
            {
                if (data[varend] == '%' || (!std::isalpha(data[varend]) && data[varend] != '_'))
                    break;

                ++varend;
            }

            if (varend >= endpos || data[varend] != '%')
            {
                // Comment without a variable.
                pos = endpos + 1;
                continue;
            }

            // Insert previous literal.
            if (newpos > lastpos)
            {
                _segments.emplace_back(SegmentType::Data, data.substr(lastpos, newpos - lastpos));
            }

            lastpos = endpos + 1;
            _segments.emplace_back(SegmentType::CommentedVariable,
                                   data.substr(varstart + 1, varend - varstart - 1));
        }
        else
        {
            assert(data[newpos] == '%' && "Expected '%' at given position");

            // Extract variable name.
            std::size_t varend = newpos + 1;
            while (varend < _size)
            {
                if (data[varend] == '%' || (!std::isalpha(data[varend]) && data[varend] != '_'))
                    break;

                ++varend;
            }

            if (varend > _size || data[varend] != '%')
            {
                // Broken variable.
                pos = varend;
                continue;
            }

            // Insert previous literal.
            if (newpos > lastpos)
            {
                _segments.emplace_back(SegmentType::Data, data.substr(lastpos, newpos - lastpos));
            }

            lastpos = varend + 1;
            _segments.emplace_back(SegmentType::Variable,
                                   data.substr(newpos + 1, varend - newpos - 1));
        }

        pos = lastpos;
    } while (pos < _size);

    if (lastpos < _size)
    {
        _segments.emplace_back(SegmentType::Data, data.substr(lastpos));
    }
}

std::string PreProcessedFile::substitute(const Util::UnorderedStringMap<std::string>& values)
{
    std::string recon;
    recon.reserve(_size * 2);
    for (const auto& seg : _segments)
    {
        switch (seg.first)
        {
            case SegmentType::Data:
                recon.append(seg.second);
                break;
            case SegmentType::Variable:
            case SegmentType::CommentedVariable:
            {
                const auto it = values.find(seg.second);
                if (it == values.end())
                {
                    // Leave original variable as-is.
                    if (seg.first == SegmentType::Variable)
                    {
                        recon.push_back('%');
                        recon.append(seg.second);
                        recon.push_back('%');
                    }
                    else if (seg.first == SegmentType::CommentedVariable)
                    {
                        recon.append("<!--%");
                        recon.append(seg.second);
                        recon.append("%-->");
                    }
                }
                else
                {
                    // Substitute with the given value.
                    recon.append(it->second);
                }
            }
            break;
        }
    }

    return recon;
}

std::string FileServerRequestHandler::uiDefaultsToJSON(const std::string& uiDefaults, std::string& uiMode, std::string& uiTheme, std::string& savedUIState)
{
    Poco::JSON::Object json;
    Poco::JSON::Object textDefs;
    Poco::JSON::Object spreadsheetDefs;
    Poco::JSON::Object presentationDefs;
    Poco::JSON::Object drawingDefs;

    uiMode.clear();
    // Leave the theme unset unless ui_defaults names one (UITheme below). A
    // normal request that does not set ui_defaults then keeps the empty theme it
    // had before, instead of being forced to "light"; the client decides the
    // theme from its own settings. (Previously a process-global cache returned
    // early for the common empty input and masked this default.)
    uiTheme.clear();
    savedUIState = "true";
    StringVector tokens(StringVector::tokenize(uiDefaults, ';'));
    for (const auto& token : tokens)
    {
        StringVector keyValue(StringVector::tokenize(tokens.getParam(token), '='));
        Poco::JSON::Object* currentDef = nullptr;
        std::string key;

        // detect the UIMode or component
        if (keyValue.equals(0, "UIMode"))
        {
            if (keyValue.equals(1, "compact") || keyValue.equals(1, "classic"))
            {
                json.set("uiMode", "classic");
                uiMode = "classic";
            }
            else if(keyValue.equals(1, "tabbed") || keyValue.equals(1, "notebookbar"))
            {
                json.set("uiMode", "notebookbar");
                uiMode = "notebookbar";
            }
            else
                LOG_ERR("unknown UIMode value " << keyValue[1]);

            continue;
        }

        // detect the UITheme default, light or dark
        if (keyValue.equals(0, "UITheme"))
        {
            if (keyValue.equals(1, "dark")) {
                json.set("darkTheme", "true");
            } else {
                json.set("darkTheme", "false");
            }
            uiTheme = keyValue[1];
            continue;
        }
        if (keyValue.equals(0, "SavedUIState"))
        {
            if (keyValue.equals(1, "false"))
            {
                savedUIState = "false";
            }
            else
            {
                if (!keyValue.equals(1, "true"))
                {
                    LOG_ERR("unknown SavedUIState value " << keyValue[1]);
                }
                savedUIState = "true";
            }
        }
        if (keyValue.equals(0, "SaveAsMode"))
        {
            if (keyValue.equals(1, "group"))
            {
                json.set("saveAsMode", "group");
            }
            continue;
        }
        if (keyValue.equals(0, "TouchscreenHint"))
        {
            json.set("touchscreenHint", keyValue[1]);
            continue;
        }
        if (keyValue.equals(0, "OnscreenKeyboardHint"))
        {
            json.set("onscreenKeyboardHint", keyValue[1]);
            continue;
        }
        else if (keyValue.startsWith(0, "Text"))
        {
            currentDef = &textDefs;
            key = keyValue[0].substr(4);
        }
        else if (keyValue.startsWith(0, "Spreadsheet"))
        {
            currentDef = &spreadsheetDefs;
            key = keyValue[0].substr(11);
        }
        else if (keyValue.startsWith(0, "Presentation"))
        {
            currentDef = &presentationDefs;
            key = keyValue[0].substr(12);
        }
        else if (keyValue[0].starts_with("Drawing"))
        {
            currentDef = &drawingDefs;
            key = keyValue[0].substr(7);
        }
        else
        {
            LOG_ERR("unknown UI default's component " << keyValue[0]);
            continue;
        }

        assert(currentDef);

        // detect the actual UI widget we want to hide or show
        if (key == "Ruler" || key == "Sidebar" || key == "Statusbar" || key == "Toolbar")
        {
            std::string value("true");
            if (keyValue.equals(1, "false") || keyValue.equals(1, "False") || keyValue.equals(1, "0"))
                value = "false";

            currentDef->set("Show" + key, value);
        }
        else
        {
            LOG_ERR("unknown UI default " << keyValue[0]);
            continue;
        }
    }

    if (textDefs.size() > 0)
        json.set("text", textDefs);

    if (spreadsheetDefs.size() > 0)
        json.set("spreadsheet", spreadsheetDefs);

    if (presentationDefs.size() > 0)
        json.set("presentation", presentationDefs);

    if (drawingDefs.size() > 0)
        json.set("drawing", drawingDefs);

    std::ostringstream oss;
    Poco::JSON::Stringifier::stringify(json, oss);

    return oss.str();
}

std::string FileServerRequestHandler::checkFileInfoToJSON(const std::string& checkfileInfo)
{
    static std::string previousCheckFileInfo;
    static std::string previousCheckFileInfoJSON("{}");

    // early exit if we are serving the same thing
    if (checkfileInfo == previousCheckFileInfo)
        return previousCheckFileInfoJSON;

    Poco::JSON::Object json;
    StringVector tokens(StringVector::tokenize(checkfileInfo, ';'));
    for (const auto& token : tokens)
    {
        StringVector keyValue(StringVector::tokenize(tokens.getParam(token), '='));
        if (keyValue.equals(0, "DownloadAsPostMessage"))
        {
            bool value(false);
            if (keyValue.equals(1, "true") || keyValue.equals(1, "True") || keyValue.equals(1, "1"))
                value = true;
            json.set(keyValue[0], value);
        }
    }
    std::ostringstream oss;
    Poco::JSON::Stringifier::stringify(json, oss);
    previousCheckFileInfo = checkfileInfo;
    previousCheckFileInfoJSON = oss.str();
    return previousCheckFileInfoJSON;
}

namespace
{
constexpr bool isValidCss(const std::string_view token)
{
    constexpr std::string_view forbidden = "<>{}&|\\\"^`'$[]";
    for (auto c: token)
    {
        if (c < 0x20 || c >= 0x7F || forbidden.find(c) != std::string::npos)
            return false;
    }
    return true;
}
}

std::string FileServerRequestHandler::cssVarsToStyle(const std::string& cssVars)
{
    static std::string previousVars;
    static std::string previousStyle;

    // early exit if we are serving the same thing
    if (cssVars == previousVars)
        return previousStyle;

    std::ostringstream styleOSS;
    styleOSS << ":root {";
    StringVector tokens(StringVector::tokenize(cssVars, ';'));
    for (const auto& token : tokens)
    {
        const std::string param = tokens.getParam(token);
        StringVector keyValue(StringVector::tokenize(param, '='));
        if (keyValue.size() < 2)
        {
            static bool warnedOnce = false;
            if (!warnedOnce)
            {
                warnedOnce = true;
                LOG_ERR("Skipping the token ["
                        << param << "] since it "
                        << (param.ends_with('=') ? "is empty" : "does not have '='"));
            }

            continue;
        }
        else if (keyValue.size() > 2)
        {
            LOG_ERR("Skipping the token [" << param << "] since it has more than one '=' pair");
            continue;
        }

        if (!isValidCss(param))
        {
            LOG_WRN("Skipping the token [" << param << "] since it contains forbidden characters");
            continue;
        }

        styleOSS << keyValue[0] << ':' << keyValue[1] << ';';
    }
    styleOSS << "}";

    previousVars = cssVars;
    previousStyle = macaron::Base64::Encode(styleOSS.str());

    return previousStyle;
}

/* vim:set shiftwidth=4 softtabstop=4 expandtab: */